package com.lagou.homework;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;

import java.io.IOException;

public class NumberDriver {

    public static void main(String[] args) throws IOException, ClassNotFoundException, InterruptedException {

        //1. 获取配置文件对象，获取job对象实例
        Configuration conf = new Configuration();
        Job job = Job.getInstance(conf, "number-driver");
        //2. 指定程序jar的本地路径
        job.setJarByClass(NumberDriver.class);
        //3. 指定Mapper/Reducer类
        job.setMapperClass(NumberMapper.class);
        job.setReducerClass(NumberReducer.class);
        //4. 指定Mapper输出的kv数据类型
        job.setMapOutputKeyClass(NumberBean.class);
        job.setMapOutputValueClass(NullWritable.class);
        //5. 指定最终输出的kv数据类型
        job.setOutputKeyClass(NumberBean.class);
        job.setOutputValueClass(NullWritable.class);
        //5.1 是否使用combiner
        //5.2是否使用自定义分区器; 是否指定reduceTask数量; reduceTask数量和分区数量要保持一致
        //因为要全局排序, 所以指定mapTask数量为1
        job.setNumReduceTasks(1);

        //6. 指定job处理的原始数据路径
        FileInputFormat.setInputPaths(job, new Path("d:/aaa/homework/input"));
        //7. 指定job输出结果路径
        FileOutputFormat.setOutputPath(job, new Path("d:/aaa/homework/output"));
        //8. 提交作业
        boolean flag = job.waitForCompletion(true);

        System.exit(flag ? 0 : 1);
    }
}
